Error Detection Based On He-Ne Laser Beam Drift

In the research of laser countermeasure technology, laser beam drift is the inherent character of laser weapon system. Based on He-Ne laser, error of beam drift is detected. The running principle of He-Ne laser is introduced, and the structure of intra-cavity He-Ne laser is parsed. The factors of He-Ne laser beam drift are analyzed theoretically. It is illuminated stressfully that the difference of temperature between cathode and anode in laser resonator is the main factor of bringing laser parallel drift and angle drift. The influences of beam drift against laser weapon system are discussed, and the measures of minishing beam drift are brought forward. On the aspect of detection of beam drift, it is pointed out that the type of 13PSQ002 Quadrantal Photodiode(QPD) is the crucial component in the experiment system. The output opto-electronic current is calculated theoretically. Calculating formula of QPD localizing the centre of laser spot is deduced. During the course of design of experiment system, the designs of optical system and circuit system for detecting beam drift are completed. On the aspect of optical system design, it is creatively adopted the method of focusing and contracting beam to control laser beam. The detecting precision is improved greatly. Utilizing long focus collimating lens, it is successfully separated beam parallel drift and angle drift. Beam angle drift is precisely detected. After the completion of experiment, raw data of experiment is registered. By means of calculating formula, the quantum of beam parallel drift and angle drift is gained. The characteristic curves of beam parallel drift and angle drift are portrayed with the variances of time and light distance. The errors of beam parallel drift and angle drift are calculated , and the reasons of producing these errors are analyzed too. Finally, the experiment result is concluded.